Thrown in at the deep end! Will I synth or swim?

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  • Updated 5 years ago
Hi all - I've got a corporate shoot coming up in 10 days for which they want me to shoot 30 or so 'sites' over three days, with each site becoming a photosynth. I haven't done a synth before, so I was wondering if someone might give me some good advice on shot selection/camera position/what works and what doesn't. Also, can you upload files of different resolution for the same synth (ie. use lo-res shots of areas that have no interest)? People and movement? Small scenes? I know nothing.

Any and all help/advice/gentle words of nurture would be greatly appreciated. Thanks.

Richard Cooper
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Richard Cooper

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  • not entirely sure of anything

Posted 5 years ago

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David Gedye, Principal Group Manager

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Richard -- my advice is start small (20-50 photos), and start practicing NOW. You should of course read our guide to photographers.
Resolution doesn't matter (the more the better), but exactly how you cover the area with photos does. Read the doc, practice, and ask questions about your results on our forums on the Photosynth site.
Good luck!
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Richard Cooper

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Many thanks David - I'm on it now...
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Nathanael Lawrence

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Richard, in addition to the Photosynth Photography Guide, here's the tutorial video.

How to Synth with Laura Foy


To get you jump started into synthing theory, I'm going to link you to some conversations where people are reporting how things have gone wrong for them and where myself or others have tried to explain what to do differently. As you suggest, sometimes knowing what not to do is as helpful as knowing the right thing to do and the best teacher is experience, so take as much as you can from our experiences. Don't be put off by people's failures. Everyone is somewhere on the learning curve and no one has mastered everything, but it's more than possible to get satisfying results.

A few quick pointers before you hit the reading assignments:

1: I'll tell you right away that my personally biased favourite technique from the guide and the video tutorial (for purposes of 3D modeling) is orbits - that is to say circling an object. In the following links this will become increasingly clear. There's nothing in Photosynth that necessarily requests circular camera motions, but rather it is trying to identify the same points in multiple images and it only does this well if the photos are taken with a difference of less than 25 degrees moving around a subject. You make the matching that much simpler if you maintain a particular distance and when you are maintaining a particular distance and varying your perspective on a subject, you end up with an orbit or a series of orbits. Taken to the extreme, this would result in full spherical coverage of an object which would be amazing, but is not necessary.

Examples: If you want to see see a tree's trunk in the 3D point cloud, then circle the trunk with photos. If you want to see the fire hydrant in the point cloud, then circle it with photos. If you want to see the vintage door handle in the point cloud, then circle it with photos. If you want to see the inscription carved below a sculpture, don't be afraid to circle the letters with photos. You get my point. ツ It's possible to overdo this, but almost all people new to Photosynth err in the opposite direction of just glancing at things as they shoot a series of panoramas. (I personally made this mistake when I first began, so I'm not criticizing anyone too unfairly.)

2: Try to take no fewer than 24 photos when circling something.

3: Stop thinking of things as whole objects and think more about individual surfaces. i.e. "Have I captured the wall or door or welcome mat of this house from a reasonable number of angles?", rather than thinking of the entire house as one object.

4: If you want more points, zoom in or get closer (just as when you want more pixels of a subject, you zoom in or get closer).

5: As the above points probably make clear, shooting photosynths is extremely different than shooting panoramas. Although Photosynth now hosts panoramas stitched by Microsoft ICE, the techniques used to shoot a clean panorama (no parallax) and the techniques to shoot a synth for purposes of 3D reconstruction (maximize parallax) are inverse to each other.

6: Scale matters. If you have an extremely wide shot and a close up, you'll need to have some intermediate shots walking between those vantage points. A little secret about Photosynth is that, although it uploads the full resolution photos, it only scans for image features to then match at 1.5 to 2 megapixels, so as to be able to put more photos together. Think of the wide angle shot of that object in the distance. It doesn't matter if you're shooting at 24 megapixels; in terms of whether Photosynth is going to match it to the close up, you've got to think of the number of pixels that little subject is going to be represented by when Photosynth looks at a 1.5 megapixel version of the whole frame. The difference between that and when that object fills up the frame (even only a 1.5 megapixel frame) is substantial. The good news is simply that if you don't let the percentage of the frame that something occupies more than double between the two closest shots of it, the matching should do just fine.

The discussions I alluded to above.

Synth not 360 (not including all photos)?

How to select where photos overlap?

Linking issues on a massive Synth

Biggest Synth Possible

This is MADDENING

Why the photo resolution doesn't matter:
Best size for each image?

A couple of other videos to help you get a sense of what's going on:

Photosynth on GeekBrief with Cali Lewis and David Gedye


ShutterSpeed Episode 04 - The Photosynth Team with Nic Fillingham, Blaise Agüera y Arcas, Drew Steedly, and Scott Fynn


My street cred to help you decide whether you want to listen to me or not.
(Use the [ P ] key to toggle from Photos Only to Photos + Points to Points Only...)

Orbital Propulsion: Gravity Assist
by Nathanael containing 731 Photos which were 100% Synthy

The Beaver Grove Sign
by Nathanael containing 717 Photos which were 100% Synthy

Oregon Veterans Medal of Honor Memorial
by Nathanael containing 760 Photos which were 100% Synthy

Charles and Waltraut's Hospitality
by Nathanael containing 284 Photos which were 100% Synthy

Memorials at Oregon's Capitol
by natelawrence containing 1376 Photos which were 100% Synthy

Deep Wood House: South Lawn (Last 1200)
by Nathanael.Lawrence containing 1200 Photos which were 100% Synthy

Deep Wood House: Greenhouse
by Nathanael containing 1692 Photos which were 93% Synthy

Salem Capitol Lobby (Very Rough Draft)
by Nathanael containing 1751 Photos which were 89% Synthy

Pro tips for analysing synths:

1: Use the full stop [ . ] and comma [ , ] keys to travel through the photos in a synth in the order of their filenames, rather than the default Photosynth spatial order. This allows you to follow the steps of the photographer (provided that the synth is not a mix of multiple different shoots with duplicated filenames between the sets). (This is most effective in synths with high synthy percentages because you won't be teleported between different groups of photos because there will only be one group of photos.) A full listing of the keyboard commands can be found at the end of the Photography Guide.

2: If you own an iPod Touch or iPhone, quickly download the free iSynth app. It includes an invaluable feature which no other Photosynth viewer currently offers which is to be able to see all of the camera positions in the context of the point cloud. Load up the most interesting synths in the app and you can plainly see what camera movement the best photosynth authors have used to achieve their results.

3: Use 2D View to understand which photos are matching together and how many clusters of photos are in a synth. You can use the icon in the Photosynth viewer or just press the [ ~ ] key to toggle between 2D and 3D.

4: If you're running Windows and have the Photosynth app installed, scroll to the bottom of any synth's viewing page and look on the lower left for a link to the older Direct3D Photosynth viewer, as it's faster and smoother and better for viewing point clouds..

Provisos:

I am very point cloud centric, but an excellent Photosynth doesn't have to be:
Campanario de Dumaguete
by almostchristian containing 18 Photos which were 100% Synthy

Still Life with 40 Apples
by David containing 35 Photos which were 100% Synthy

Climbing Sentinel (with highlights)
by K containing 408 Photos which were 96% Synthy

Provided that you get enough overlap, shooting multiple panoramas can work.
Catalina Island California
by robert_sprout containing 349 Photos which were 100% Synthy

Further Recommended viewing:

Mika And Herself // 3D Magic Trick // Go Game

Hiroshima A-Bomb Dome! (guided tour, and scavenger hunt!)

Jennie // Professional Go Game

Huge House (with highlights)

Cenote Samula, Valladolid, Yucatán

Martello Tower: Inside & Out

Kiholo Bay Inlet - Kite Aerial (KAP)

What is in the old Coffee Mill ? / SYNTHOMAGIC

What is in the apple ? / SYNTHOMAGIC

Lily

Banana Joe

Guitar Workshop

Santa Barbara Courthouse // Inside and Out

Lily - Red Rum

Nine Dragon Screen Wall, Forbidden City, Beijing

Cologne Cathedral - Kölner Dom, Germany

Regis University Main Hall and Chapel Combined

Hang Gliding over Yosemite Valley

Stela "M"

National Geographic - Sphinx

National Geographic: Stonehenge Revealed

National Geographic: Hagia Sophia - Grand Hall

National Geographic - Roman Colosseum

Photosynth Pumpkin 2.2

The Nose

"Doug"

Kew House Photosynth

Face Study #01 - Point Cloud Density

Lana's Face

Nellie Inglerock - Masonic Cemetery

iNveridux - Intestinal Man's Petroglyphs

Medieval Castle, Guimarães, Portugal

Martin Luther King Jr. Memorial Park

US Constitution - National Archives

US National Archives - Constitution (With Highlights)

Gary Faigin Studio

Grassi Lakes by Pat Morrow

notre dame de paris

Boulder Dushanbe teahouse

Garden

Engaged at Pulhapanzak (with highlights)

Tom the Sleeping Kitten

The KittCave

Passage / Przejscie, Wroclaw, Poland

App Wall @ WWDC

1970 Volkswagon Beach Buggy

Trinity Rep Skylight

Torrey Pines State Reserve beach trail

Liana W Gray

Cathedral of the Most Holy Trinity (Bermuda)

My first photosynth

Christ the Redeemer

Sub Antarctic House

Another Tres Yonis Synth

church

Brayfield House, Cold Brayfield

Noah Snavely, Cornell University

Original Seadragon Office

How to Synth video: Interiors

How To Synth Video: Gasworks Park

GeekBrief synth with Cali Lewis

"Unfinished" Church St. George's Bermuda
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Richard Cooper

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Nathanael - this is excellent, big thanks for the links.
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Nathanael Lawrence

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Any results yet, Richard? If you're allowed to share any of the synths, I'd be interested in seeing your first attempts. If that's not possible due to your client's requests, I can understand.